The regulation of Saccharomyces cerevisiae membrane-associated phosphatidate phosphatase (3-sn-phosphatidate phosphohydrolase, EC 3.1.3.4) activity by sphingoid bases was examined using Triton X-100/lipid-mixed micelles. Sphingosine, phytosphingosine, and sphinganine inhibited purified preparations of the 104- and 45-kDa forms of phosphatidate phosphatase in a dose-dependent manner. The structu...

The intracellular signalling pathway for alpha-adrenoceptor-mediated negative inotropy was studied pharmacologically in isolated adult mouse ventricle. The negative inotropy was inhibited by GF-109203X, a nonselective protein kinase C inhibitor. Phorbol 12-myristate 13-acetate also produced sustained negative inotropy, which was inhibited by KB-R7943, a Na(+)/Ca(2+) exchanger inhibitor. The alp...

1. Microsomal membranes from rat liver were incubated with ATP, CoA, Mg2+, [14C]palmitate, Fand sn-glycerol 3-phosphate in order to label them with [14C]phosphatidate. These membranes were isolated and used in a second incubation in which [3H]CTP was present, and the simultaneous synthesis of [14C]diacylglycerol and [3H]CDP-diacylglycerol was measured. 2. The addition of phosphatidate phosphohy...

Feeding rats with sorbitol, fructose, glycerol and ethanol increases the concentration of serum corticosterone without significantly altering the concentration of insulin. This increase appears to be partly responsible for the increases in the hepatic activity of phosphatidate phosphohydrolase (compared with rats fed glucose or 0.9% NaCI) that has been reported [Sturton, Pritchard, Han & Brindl...

The purpose of this work is to compare the properties of phosphatidate phosphatase (L-alpha-phosphatidate phosphohydrolase, EC 3.1.3.4) in fetal and adult rat lung and to establish the developmental profile of activity measured under optimal conditions. The maximal pH of 6.0--7.0 and the inhibition by fluoride, Ca2+ and detergents were simialr for both adult and fetal. Phosphatidate phosphohydr...